Ceramic composite materials have been proposed for a variety of applications. In certain types of nozzles, turbine blades and rotors, heat conducting tubes, crucibles, etc., the working temperatures can be as high as 1,700 to 1,800.degree. C. while experiencing mechanical loads up to 400 MPa. For short periods of time temperatures can exceed 2,500.degree. C. Thus, materials used to make these products should be both heat and impact resistant, as well as fracture tough.
For anti-ballistic applications, a suitable material for making personal bullet-proof vests, armor protection against anti-tank weapons, bullet-proof automobiles, and numerous other armor applications, should be impact resistant, light weight, and wherever possible, made of cost-effective, relatively light materials.
There is a significant demand for materials that are light but hard, that have high fracture toughness at high temperatures, and are highly thermal-shock resistant, and can withstand highly aggressive/corrosive environments. Products made from materials with such properties will be able to achieve major breakthroughs in a myriad of applications, including high temperature, high-load applications, both in air and in chemically aggressive environments. Furthermore, there is a need for light-weight materials with high fracture toughness for a wide range of anti-ballistic (armor) applications.
Boron carbide is a suitable material for some of these applications. However, the application domains in which boron carbide can be used are limited by its negative qualities, such as brittleness (2-3 MPa.times.m.sup.0.5), low resistance to heat, loss of strength at high temperature, and low thermal-shock resistance.
U.S. Pat. No. 4,678,759 describes a ceramic composite material containing boron carbide, silicon carbide, zirconium boride, and aluminum nitride. However, this material has relatively low high-temperature strength, low thermal-shock resistance, and is further restrained by a relatively complicated production process.
U.S. Pat. No. 4,320,204 describes another ceramic composite material containing boron carbide, silicon carbide, and aluminum. As in the previous prior art patent, this material has drawbacks, including relatively low high-temperature strength, low thermal-shock resistance and low fracture toughness.
Thus, a continuing need exists for an improved ceramic composite material capable of achieving improved physical properties and performance characteristics.